Novel hydrophilic adhesive compositions

ABSTRACT

The present invention relates to novel hydrophilic adhesive compositions, characterised in that they comprise a thermoplastic elastomer of poly(styrene-olefin-styrene) block copolymer type, a tackifying product, a liquid plasticizer, water and un amphiphilic copolymer. The invention also relates to the use of these novel hydrophilic adhesive compositions as adhesives for fixing any type of product, and notably products for medical, dermatological or cosmetological purposes, which come into contact with a wound, the skin or the mucous membranes.

The present invention relates to novel hydrophilic thermofusibleadhesive compositions, characterised in that they comprise athermoplastic elastomer of poly(styrene-olefin-styrene) block copolymertype, a tackifying product, a liquid plasticizer, water and anamphiphilic copolymer.

The invention also relates to the use of these novel hydrophilicadhesive compositions as adhesives for fixing any type of product andnotably products for medical, dermatological or cosmetological purposeswhich come into contact with a wound, the skin or the mucous membranes.

The preparation of adhesive compositions based on a thermoplasticelastomer of poly(styrene-olefin-styrene) block copolymer type has beenknown for a long time.

Thus, pressure-sensitive adhesives are prepared from compositions whichcomprise a poly(styrene-olefin-styrene) block copolymer, a tackifyingproduct, such as, for example, a tackifying resin and a liquidplasticizer, such as, for example, a plasticizing oil, as essentialconstituents.

Such compositions are thus defined in the <<Handbook of PressureSensitive Adhesive technology>> 2^(nd) Edition, edited by Donatas Satasin 1989, Chapter 13, pages 317 to 359.

These adhesives are used in very many industrial applications since theypossess good mechanical properties (elasticity, cohesion, adhesiveness)that can be modulated by adjusting the nature (grade, viscosity,polarity, molar mass, etc . . . ) and the proportion of the threeessential constituents which are the plasticizer, the tackifying productand the block copolymer.

The main drawback of the adhesive compositions hitherto known originatefrom their exclusively hydrophobic nature, which renders themincompatible with water or hydrophilic products.

It is known to render these formulations more hydrophilic byincorporating therein fillers, such as, for example, cellulosederivatives, such as sodium carboxymethylcellulose, but this complicatesthe preparation of them and increases the manufacturing costs of them.

Moreover, the incorporation of water with such compositions causes theswelling of the hydrophilic filler and the loss of the good mechanicalproperties of the composition, such as its adhesiveness and itscohesion.

Today, there does not therefore exist a stable adhesive compositionwhich can contain water, even in a low amount.

It is furthermore known within the context of a use on the skin, a woundor the mucous membranes, which constitute specific supports, that anadhesive must fulfil complex demands, and particularly it must have anacceptable appearance for the user, it must not lead to problems oftolerance during its use, nor cause pain or leave traces upon removal,and all this in preserving its adhesive, cohesive and elastic propertiesduring its use.

Moreover, it is desirable to be able to incorporate in the adhesive,which then serves as a reservoir and as a delivery means, variouscompounds, such as, for example, pharmaceutical, cosmetological ordermatological actives.

Adhesives which are more particularly intended to be used on the skin, awound or the mucous membranes, are thus described in the patentapplications EP 758 009, EP 723 571 and EP 991 730.

However, the adhesives described in these patent applications still havemany drawbacks and do not enable a certain number of problems to besolved satisfactorily.

Thus, in certain applications which necessitate the addition of liquidplasticizers an a relatively significant amount, very often oils, theadhesive does have a greasy or oily appearance from this, which lacksapproval for the user. Furthermore, the migration of these plasticizerscan lead to the appearance of marks or rings on the elements combinedwith the adhesive, such as, for example, the support, in the case of apatch, even to soiling the clothes in contact with this support.

Additionally, by virtue of their hydrophobic nature, the known adhesiveshave an occlusive effect which often leads to a maceration, whichmanifests itself by problems of tolerance during their use. Thisocclusive effect also manifests itself by the appearance of an aqueousinterface which leads to a loss in the adhesion and to the correlativepeeling off of the product, notably in case of sweating or during theproduction of exudates.

Finally, by virtue of this hydrophobic nature, it is very difficult, andsometimes even impossible, to incorporate hydrophilic actives in thesecompositions, the use of which can prove to be very useful, evenindispensable in certain applications, such as, for example, anantiseptic, such as chlorhexidine digluconate, or plant extracts in thecosmetic field, or even electrolytes within the context of thepreparation of electrodes.

The presence of water in the products intended to be applied on theskin, the mucous membranes or on a wound brings about a sensation offreshness, or of cold; enables the appearance of the final product to beimproved, which appears less greasy; enables moisturising and softeningthe tissues by forming a moisturising film which promotes thehydro-physiological equilibrium of the skin, of a wound or of the mucousmembranes, by thus avoiding the above-mentioned problems of tolerance.

It is for this reason that in the medical, dermatological or cosmeticfields, hydrogels are preferably used in contact with the skin, a woundor the mucous membranes. These hydrogels contain large amounts of water,often of the order of 30 to 80% by total weight with respect to thetotal weight of the hydrogel, and natural high-molecular weightpolymers, such as, for example, polysaccharides, particularlyglucomananes, galactomananes, carragheens; or synthetic polymers whichare often cross-linked, in order to ensure the cohesion of the adhesivehydrogel, such as, for example, copolymers based on2-acrylamido-2-methylpropanesulfonic acid, which are marketed by thecompany LUBRIZOL under the designation AMPS®.

However, these hydrogels possess insufficient adhesion and cohesionproperties. From this, they disintegrate and peel off easily, thesurface of the adhesive is often altered or polluted by contact with theskin, a wound or the mucous membranes, and in general they are notrepositionable once peeled off.

In contrast to the adhesives, and due to their hydrophilic nature, it isvery difficult, even impossible to incorporate lipophilic or hydrophobicproducts with these hydrogels, and this consequently leads to the sameproblems of formulation as set forth above.

Finally, the implementation of the hydrogels is in general more delicateand more complex than that of the adhesives.

Taking into account this state of the art, it would therefore bedesirable to have novel adhesive compositions at one's disposal whichwould combine the advantages of the known adhesives, namely to possessgood properties of adhesion, of cohesion and of elasticity; and theadvantages of the hydrogels, namely to possess a hydrophilic characterand to contain water, even in very low amount.

Adhesives would thus be at one's disposal the hydrophilic character ofwhich adhesives would lead to better performances and would open theirfield of use to new applications. Within the context of the applicationsfor medical, cosmetic, pharmaceutical or dermatological purposes, inwhich there is a contact with the skin, a wound or the mucous membranes,an adhesive composition would be at one's disposal which is not veryaggressive, which is well-tolerated, if necessary re-positionable, inwhich it would be possible to incorporate hydrophilic or lipophiliccompounds, the use of which is pleasant, and susceptible to bringingabout a sensation of freshness, which is simple to use, which is stableand which keeps its properties of adhesion and of cohesion during itsuse.

An aim of the present invention is novel, hydrophilic adhesivecompositions which fulfil these aims and which notably enable theproblems of incompatibility and of affinity of known adhesives withwater and hydrophilic products, to be solved.

It has been discovered and this constitutes the basis of the presentinvention, that it was possible to render hydrophilic an adhesivecomposition based on a thermoplastic elastomer ofpoly(styrene-olefin-styrene) block copolymer type satisfactorily, andsimple to use, by incorporating therein an amphiphilic copolymer ofpoly(styrene-ethylene-butylene-styrene) type which is grafted withhydrophilic groups. Such a composition can incorporate water orhydrophilic products, without loosing its basic properties.

Thus, according to a first aspect, the present application covers ahydrophilic adhesive composition, characterised in that it comprises:

-   -   a thermoplastic elastomer, which is selected from the block        copolymers poly(styrene-olefin-styrene), poly(styrene-olefin),        and their mixtures,    -   a tackifying product,    -   a liquid plasticizer,    -   water, and    -   an amphiphilic ABA type block copolymer comprising two terminal        thermoplastic poly(styrene) blocks A and one central elastomeric        block B in which the central block B is a        poly(ethylene-butylene) sequence comprising grafted hydrophilic        groups, it being possible for said copolymer ABA to be        represented schematically by the following structure        in which R₁ and R₂, which are identical or different, represent        a hydrophilic group of average molar mass less than 10,000,        which is selected from the following groups:        in which n, a and b represent an integer.

The hydrophilic adhesive compositions according to the invention thuspossess a very wide range of properties which renders their exploitationpossible in very many fields, and particularly in the preparation ofproducts intended to be used in contact with the skin, a wound or themucous membranes.

According to a second aspect, the present application covers the use ofthese novel hydrophilic adhesive compositions as adhesives for fixingany type of product, and notably products for medical, dermatological orcosmetological purposes which come into contact with a wound, the skinor the mucous membranes.

The detailed description that follows of the various constituents of thehydrophilic adhesive composition according to the invention will enableto better understanding the nature and the applications of thisinvention.

DESCRIPTION OF THE INVENTION

The amphiphilic copolymer which is used in the preparation of thehydrophilic adhesive compositions according to the invention is an ABAtype block copolymer comprising two terminal thermoplastic poly(styrene)blocks A and one central elastomeric block B, in which this centralblock B is a poly(ethylene-butylene) sequence comprising graftedhydrophilic groups, it being possible for said amphiphilic copolymer ABAto be represented schematically by the following structure:

in which R₁ and R₂, which are identical or different, represent ahydrophilic group of average molar mass of less than 10,000, selectedfrom the following groups:

in which n, a and b represent an integer.

Advantageously, within the context of the present invention, theamphiphilic copolymers will be preferred in which R₁ and R₂ areidentical.

Amongst these, the amphiphilic copolymers will preferably be used inwhich R₁ and R₂ represent a CH₃—O—(CH₂—CH₂—O)_(n) group, particularly ofaverage molar mass of between 1,000 and 8,000 and more particularly ofaverage molar mass equal to 2,000 (i.e.=45).

These amphiphilic copolymers are obtained by grafting hydrophiliccompounds onto a particular SEBS copolymer.

This particular copolymer comprises succinic anhydride functions whichare distributed along the elastomeric poly(ethylene-butylene) chain,which are obtained by reaction of maleic anhydride with thepoly(ethylene-butylene) sequence, and which will be called “maleatedSEBS” in the following.

This maleated SEBS copolymer, which serves as the basis for thepreparation of the amphiphilic copolymers according to the invention,can be represented schematically by the following formula:

For reasons of simplicity, only one sole succinic anhydride group hasbeen represented in this formula on the poly(ethylene-butylene)sequence. It is obvious that this sequence in reality comprises severalsuccinic anhydride groups. This simplification has also been used inorder to schematically represent the amphiphilic copolymers used withinthe context of the present invention.

A maleated SEBS marketed by the company SHELL under the designationKraton G 1901® will be preferred as maleated SEBS, which contains 2% byweight of succinic anhydride functions fixed onto the elastomeric chainand 28% by weight of polystyrene.

It is these anhydride functions which will serve to graft thehydrophilic compounds by chemical reaction between the hydrophiliccompound and the anhydride or its acid form.

According to the conditions of storage, and particularly according tothe degree of drying of this maleated SEBS, a part of these succinicanhydride functions can in fact be present as their acid forms afteropening of the anhydride in the presence of water. The reaction thentakes place as well between the acid functions and the hydrophiliccompound.

The hydrophilic compounds which are grafted onto the maleated SEBS areof 3 types:

A/ Polyethyleneglycols, Hereinafter Referred to as the Abbreviation“PEGs”

These are hydrophilic, hygroscopic and heat-stable polymers. They areused in very many industrial fields. They are well-known to the personskilled in the art. They are short-chain polymers which possess hydroxylfunctions on the extremities. Their average molar mass varies from 200to 20,000.

Their composition corresponds to the following structure:

HO—(CH₂—CH₂—O)_(n)—H, in which n represents an integer.

Such products are for example marketed by the company Aldrich under thedesignation poly(ethylene glycol) followed by the average molar mass ofthe PEG considered, e.g. poly(ethyleneglycol) 2,000.

Within the context of the present invention, only amphiphilic copolymersin which the PEGs of average molar mass less than or equal to about10,000 (n thus having at the maximum a value of 230) are used. Beyond,and the grafting reaction does in fact become difficult, evenimpossible.

Advantageously, the PEGs will be used which have an average molar massof between 1,000 and 8,000, particularly the PEG which has an averagemolar mass of 2,000 (n=45).

B/ Polyethyleneglycol Mono Methyl Ethers Hereinafter Referred to as theAbbreviation “PEGMEs”

These are also short-chain polymers which are used like the PEGs in verymany fields and which are well-known to the person skilled in the art.

They have the following structure:

CH₃—O—(CH₂—CH₂—O)_(n)—H, in which n is an integer, and their averagemolar mass ranges from 200 to 20,000.

Such products are for example marketed by the company Aldrich under thedesignation poly(ethyleneglycol)methyl ether followed by the averagemolar mass of the PEGME considered, e.g. poly(ethyleneglycol)methylether2,000.

Within the context of the present invention, amphiphilic copolymers areused in which, just as for the PEGs, only the PEGMEs of average molarmass less than or equal to about 10,000 (n having at the maximum a valueof 230) are used.

Advantageously, the PEGMEs will be used which have an average molar massof between 1,000 and 8,000, particularly the PEGME which has an averagemolar mass of 2,000 (n=45).

C/ Polyethylene-Polypropyleneglycol Copolymers

These are very well-known copolymers which will be designatedhereinafter as the abbreviation PEO/PPO/PEO.

These are tri-block copolymers the central part of which is apolypropylene oxide block and the extremities of the polyethylene oxideblocks which have the following structure:

in which a and b are integers.

They are often designated as the general term “poloxamer”.

Very many grades exist for these products which are characterised by thevalues a and b which define their average molar masses. The followingcan thus be cited:

-   -   poloxamer 124: a=12 b=20 average molar mass of between 2,090 and        2,360,    -   poloxamer 188: a=80 b=27 average molar mass of between 7,680 and        9,510,    -   poloxamer 407: a=101 b=56 average molar mass of between 9,840        and 14,600.

They are marketed for example by the company BASF under the designationPluronic®.

Here, just as before, only the PEO/PPO/PEOs of average molar mass lessthan or equal to about 10,000 will be used.

Within the context of the present invention, a PEO/PPO/PEO will bepreferred of molar mass neighbouring 2,000, such as, for example, theproduct marketed under the designationpoly(ethyleneglycol)-block-poly(propyleneglycol)-block-poly(ethyleneglycol)1900, by the company Aldrich, of average molar mass equal to 1,900.

The amphiphilic copolymers which can be used within the context of thepresent invention can be prepared easily by a reaction of esterificationbetween the succinic anhydride functions of the maleated SEBS and thehydroxyl functions of the PEG, PEGME or PEO/PPO/PEO used.

The reaction of an alcohol with an anhydride function gives, reversibly,an ester. Within the context of the present invention, thisesterification can be represented by the following simplified scheme:

An excess of hydroxyl functions with respect to the anhydride functionsis introduced, so as to promote the esterification reaction.Advantageously, the reaction is catalysed by an acid, and the waterformed is removed by azeotropic distillation, in order to displace theequilibrium towards the grafted product. The reaction is preferablycarried out under an inert atmosphere.

Thus, said amphiphilic copolymers are prepared according to a method inwhich a reaction of esterification is carried out between the succinicanhydride functions borne by the poly(ethylene-butylene) part of apoly(styrene)-poly(ethylene-butylene)-poly(styrene) copolymer (maleatedSEBS) and the hydroxyl functions of a hydrophilic compound which isselected from polyethyleneglycols, (PEG), polyethyleneglycol mono methylethers (PEGME) and copolymers of polyethylene-propylene glycol(PEO/PPO/PEO) of average molar mass of less than or equal to 10,000, ortheir mixtures, preferably in the presence of an acid catalyst, byremoving the water formed and with an excess of hydroxyl functions withrespect to the succinic anhydride functions of the maleated SEBS.

More specifically, the synthetic method is the following:

The maleated SEBS is dissolved in the hot and with agitation, in asolvent, preferably toluene (at about 120° C., the reflux temperature ofthe solvent).

Apart, a solution is prepared of at least one hydrophilic compound (PEG,PEGME, PEO/PPO/PEO or their mixtures) by heating the latter compound(s)at its (their) melting temperature(s), with agitation, in a solvent,preferably toluene. Advantageously, an excess of hydrophilic compoundsis used. The number of hydroxyl functions compared to the number ofanhydride functions can thus vary from 2.5 to 20.

A catalytic amount (around a few drops) of acid, e.g. sulphuric acid, isadded, and then the solution of hydrophilic compound(s) in the solventprepared beforehand, to the solution of the maleated SEBS copolymerobtained beforehand, with agitation and keeping under reflux.

This mixture is agitated under azeotropic distillation, under reflux for30 minutes to 5 hours according to the nature of the hydrophiliccompound(s), until the complete reaction of esterification between theanhydride functions (or their eventual acid forms) of the succinicgroups of the maleated SEBS and the hydroxyl functions of thehydrophilic compound(s). The extent of the reaction is tracked by usingtechniques which are well-known to the person skilled in the art, e.g.by infrared spectroscopy until the absorption peak of the carbonyls ofthe anhydride, i.e. 1,785 cm⁻¹, has disappeared.

The reaction mixture is then precipitated in the hot at about 90-100° C.in an adequate precipitation solvent, such as, for example, ethanol oran ethanol/water mixture, said precipitation solvent representing about4 times the volume of the whole of the reaction solvents used.

After filtration, the residual solvents are removed from the amphiphilicSEBS copolymer obtained, by evaporation in the oven under vacuum at40-50° C.

It is thus necessary to purify this latter product in order to removethe hydrophilic compound(s) PEG, PEGME or PEO/PPO/PEO used in excess,which is (are) still present.

The amphiphilic polymer obtained is therefore re-dissolved underagitation at about 90 to 110° C. in toluene, and the solution obtainedis re-precipitated in the same solvent and the same volume as during theprecipitation step carried out before at the end of the synthesis.

Similarly, the amphiphilic SEBS copolymer is recovered by filtration andis dried again in the oven under vacuum at 40-50° C.

This purification step is repeated until the total removal of thehydrophilic compound(s) by checking the absence of the peak of this(these) latter compound(s), in accordance with techniques which arewell-known to the person skilled in the art, by gel permeationchromatography (GPC).

Within the context of the present invention, this amphiphilic copolymerwill be used in the adhesive compositions at a concentration of theorder of 0.05% to 20% by weight with respect to the total weight of thecomposition.

According to a preferred embodiment of the invention, an amphiphilic ABAtype block copolymer will be used comprising two terminal thermoplasticpoly(styrene) blocks A and one central elastomeric block B, in whichthis central block B is a poly(ethylene-butylene) sequence comprisinggrafted hydrophilic groups, it being possible for said amphiphiliccopolymer ABA to be represented by the following structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2000, i.e. n=45.

Such an amphiphilic copolymer will more particularly be preferred whichhas an average molar mass, measured by gel permeation chromatography, ofthe order of 50,000 daltons.

Preferably, this latter copolymer will then be used in the hydrophilicadhesive compositions at a concentration of the order of 0.05 to 20%,particularly 0.05 to 5% by weight with respect to the total weight ofthe composition.

The elastomers of (styrene-olefin-styrene) block copolymer type or(styrene-olefin) block copolymer type which can be used within thecontext of the present invention are those which are usually used by theperson skilled in the art in the preparation of pressure-sensitiveadhesives and reference in this respect may be made to the state of theart document mentioned above, and particularly to the book by DonatasSatas <<Handbook of Pressure Sensitive Technology>>.

These are therefore either ABA type triblock copolymers comprising twoterminal thermoplastic styrene blocks A and one central elastomericsequence B which is an olefin, or AB type diblock copolymers comprisinga thermoplastic styrene block A and an elastomeric sequence B which isan olefin. The olefinic sequences B of these copolymers can beconstituted of unsaturated olefins such as, for example, isoprene orbutadiene, or of saturated olefins such as, for example,ethylene-butylene or ethylene-propylene.

It will be possible, within the context of the present invention, to usethe whole of these products alone or as a mixture.

In the case of a mixture of ABA triblock copolymers and of AB diblockcopolymers, it will be possible to employ commercial mixtures of ABAtriblock copolymers and AB diblock copolymers which are alreadyavailable, or to make a mixture in any proportion selected beforehandfrom two independent products.

The products having unsaturated central sequence are well-known to theperson skilled in the art and are for example marketed by the companySHELL under the designation KRATON® D. The products marketed under thedesignations KRATON® D 1107 or KRATON® D 1161 can also be cited for thepoly(styrene-isoprene-styrene) (abbreviated to SIS) copolymers and theproduct marketed under the designation KRATON® D 1102 can be cited forexample for the poly(styrene-butadiene-styrene) copolymers. Otherpoly(styrene-isoprene-styrene) copolymers are also marketed by thecompany EXXON MOBIL CHEMICAL under the designation VECTOR®, such as, forexample, the product marketed under the designation VECTOR® 4113. Theproduct marketed by the company EXXON MOBIL CHEMICAL under thedesignation VECTOR® 4114, or the VECTOR® designated by the code DPX-565,in which B is isoprene, can be cited as examples of commercial mixturesof ABA triblock and AB diblock copolymers.

All these copolymers based on isoprene or butadiene in general have astyrene content of between 10 and 52% by weight with respect to thetotal weight of said copolymer.

Within the context of the present invention, triblockpoly(styrene-isoprene-styrene) block copolymers will be preferred havinga styrene content of between 14 and 30% by weight with respect to theweight of said SIS. The product marketed by the company SHELL under thedesignation KRATON® D 1161 will more particularly be preferred aspoly(styrene-isoprene-styrene) triblocks block copolymer, and theproduct VECTORE DPX-565, marketed by the company EXXON MOBIL CHEMICAL,as mixture of poly(styrene-isoprene-styrene) triblocks block copolymerand poly(styrene-isoprene) diblocks block copolymer.

The products having a saturated central sequence are also well-known tothe person skilled in the art and are for example marketed by thecompany SHELL under the designation KRATON® G for thepoly(styrene-ethylene-butylene-styrene) (abbreviated to SEBS) blockcopolymers such as, for example, the products marketed under thedesignations KRATON® G 1651 or KRATON® G 1654, or by the company KURARAYunder the designation SEPTON® for thepoly(styrene-ethylene-propylene-styrene) (abbreviated to SEPS) blockcopolymers.

The product the olefinic sequence of which is ethylene-butylene marketedby the company SHELL under the designation KRATON® G 1657 can be citedas an example of commercial mixtures of triblock-diblock copolymers.

The mixture of a triblock SEBS can be cited as an example of aparticular triblock-diblock mixture that can be used within the contextof the present invention, such as the product marketed by the companySHELL under the designation KRATON® G 1651, with a poly(styrene-olefin)diblock material such as the poly(styrene-ethylene-propylene) marketedby the company SHELL under the designation KRATON® G 1702.

Within the context of the present invention, SEBS or SEPS triblockcopolymers will be preferred, particularly those having a styrenecontent of between 25 and 45% by weight with respect to the weight ofsaid SEBS. The product marketed by the company SHELL under thedesignation KRATON® G 1651 will more particularly be preferred.

In general, the thermoplastic elastomer will be used according to thenature of the block copolymer, in an amount of the order of 2 to 20% byweight with respect to the total weight of the composition. Preferably,a thermoplastic elastomer will be used which has an average molar massof greater than that of the amphiphilic copolymer, preferably of theorder of 100,000 daltons. In this case, the latter thermoplasticelastomer will then preferably be used in an amount of the order of 5 to15% by weight with respect to the total weight of the composition.

If necessary, it will be possible to add anti-oxidising agents to theseblock copolymers. The term “anti-oxidising agent” is understood here asmeaning the compounds which are commonly used by the person skilled inthe art for ensuring the stability of the compounds used in theformulation of the adhesive compositions, particularly the tackifyingresins and the block copolymers, against oxygen, heat, ozone andultraviolet radiations. One or more of these anti-oxidising agents canbe used in combination.

Phenolic anti-oxidising agents, such as, for example, the productsmarketed by the company CIBA-GEIGY under the designations IRGANOX® 1010,IRGANOX® 565, IRGANOX® 1076, and sulphur-containing anti-oxidisingagents, such as, for example, zinc dibutyldithiocarbamate, marketed bythe company AKZO under the designation PERKACIT® ZDBC, can be cited asappropriate anti-oxidising agents.

Within the context of the present invention, the term “tackifying”product is understood as meaning any product which enables thecomposition to be rendered adhesive.

Given that the composition contains both a hydrophobic phase, that canbe qualified as lipophilic or oily, and an aqueous phase, thecomposition can be envisaged to be rendered adhesive by incorporating atackifying product in at least one of the two phases. It is thusadvantageously possible to employ a tackifying product which iscompatible with the oily phase, or a tackifying product which iscompatible with the aqueous phase, or even, a group of two tackifyingproducts, one lipophilic and one hydrophilic, one in each phase.

Within the context of the preparation of adhesive compositions which areintended to be applied on the skin, a wound or the mucous membranes, thepresence of water and the possibility of using two very different typesof tackifying products offer a wide range of solutions for theregulation, which is always problematic, of the bioadhesion, and inorder to prevent, upon peeling off, the alteration of the upper layersof the epidermis, or the pollution, further to this peeling off, of thesurface of the adhesive which often prevents it from being re-stuck on.

Within the context of the present invention, it will therefore bepossible to use one or more tackifying products in a wide proportion ofthe order of 1 to 50% by weight with respect to the total weight of thecomposition as a function of the other elements of this lattercomposition in order to obtain the adhesive power sought after for thefinal composition. Preferably, a tackifying product or a group oftackifying products will be used in a proportion of 2 to 30% by weightwith respect to the total weight of the composition.

Within the context of the use of 2 tackifying products, one which iscompatible with the aqueous phase, and the other with the oily phase,the group of these latter tackifying products will preferably be used ina total proportion of the order of 8 to 25% and notably of 8 to 15% byweight with respect to the total weight of the composition, particularlya proportion of the order of 2 to 5% by weight of tackifying productwhich is compatible with the aqueous phase and of 8 to 12% by weight oftackifying product which is compatible with the oily phase, and for thelatter, more particularly 10% of low molecular weight polybutene withrespect to the total weight of the composition.

The tackifying products which are compatible with the oily phase whichare susceptible in being used within the context of the presentinvention are those which are usually used by the person skilled in theart in the preparation of pressure-sensitive adhesives comprisingelastomers, and particularly poly(styrene-olefin-styrene) blockcopolymers, and it will be possible for reference to be made in thisrespect to the documents of the state of the art mentioned above, inparticular to the book by Donatas Satas.

Within the context of the present invention, these products are ingeneral selected from tackifying resins, and low molecular weightpolybutenes, or their mixtures.

Polyterpene or modified terpene resins, hydrogenated colophane resins,polymerised colophane resins, colophane ester resins, hydrocarbonatedresins, cyclic aromatic and aliphatic resin mixtures, etc . . . or theirmixtures, can be mentioned from the tackifying resins which are suitableaccording to the invention.

Such products are for example marketed by the company GOODYEAR under thedesignation WINGTACK®, particularly such as the synthetic resin formedfrom C5/C9 copolymers which is marketed under the designation WINGTACK®86 or based on synthetic polyterpene which is marketed under thedesignation WINGTACK® 10. The resins which are marketed under thedesignation KRISTALEX® by the company Hercules, particularly such as theresin based on alpha-methylstyrene, KRISTALEX® 3085, can also be citedas an example.

Within the context of the present invention, the resins marketed by thecompany EXXON MOBIL CHEMICAL under the designation ESCOREZ®, and moreparticularly the synthetic resin marketed under the designation ESCOREZ®5300, will be preferred.

Within the context of the present invention, these resins willpreferably be used in a proportion of the order of 2 to 30% by weightwith respect to the total weight of the composition as a function of theadhesive power sought after for the final composition. Moreparticularly, a proportion of resins of 5 to 25% by weight with respectto the total weight of the composition will be used.

The products which are well-known to the person skilled in the art,which are for example marketed under the designation NAPVIS® by thecompany BP CHIMIE, can be cited as low molecular weight polybuteneswhich can be used as tackifying product of the oily phase.

Within the context of the present invention, the product marketed underthe designation NAPVIS® 10 will more particularly be preferred. Thesepolybutenes can be used alone or as a mixture. They will preferably beused in a proportion of 5 to 30% by weight with respect to the totalweight of the composition, and more particularly of 8 to 15% by weight.

The tackifying products which are compatible with the aqueous phasewhich can be used within the context of the present invention areusually used by the person skilled in the art for increasing orconferring sticky properties in the presence of water. These aregenerally non-cross-linked hydrosoluble synthetic polymers, such aspolyvinylpyrrolidone polymers or polyvinylpyrrolidone copolymers, suchas, for example, the vinylpyrrolidone polymers marketed by the companyBASF under the designation KOLLIDON®, such as the product KOLLIDON® 30,polymers or copolymers of poly(vinyl alcohol), acrylic polymers,particularly such as the polyacrylates marketed by the company BFGOODRICH under the designation CARBOPOL® or the hydrosoluble polyvinylether polymers, e.g. the product marketed by the company BASF under thedesignation LUTONAL® M40.

Within the context of the present invention, these hydrosoluble polymerswill preferably be used in a proportion of the order of 1 to 30% byweight with respect to the total weight of the composition as a functionof the adhesive power sought after for the final composition. Moreparticularly, a proportion of hydrosoluble polymers will be used of theorder of 2 to 20% by weight with respect to the total weight of thecomposition.

Within the context of the present invention, the term “liquidplasticizer” is understood as meaning plasticizers which are usuallyused by the person skilled in the art for the preparation ofpressure-sensitive adhesives which comprise thermoplastic elastomers, inparticular of poly(styrene-olefin-styrene) block copolymer type andwhich are products which enable their properties of stretching,flexibility, extrudability or implementation to be improved, andreference may be made in this respect to the prior art documentsmentioned above.

These liquid plasticizers are compounds which are compatible with thecentral olefin sequence of the block copolymers used. Plasticizing oilsare used very often as liquid plasticizer, and particularly mineral oilswhich are formed from compounds of paraffinic, naphthenic or aromaticnature, or their mixtures, in variable proportions.

The products marketed by the company SHELL under the designation ONDINA®and RISELLA® can thus be cited as examples of mineral oils for themixtures based on naphthenic and paraffinic compounds, or under thedesignation CATENEX® for the mixtures based on naphthenic, aromatic andparaffinic compounds.

Within the context of the present invention, paraffin oils will bepreferred, particularly the oil marketed by the company SHELL under thedesignation ONDINA® 15.

As liquid plasticizer, not a plasticizing oil, but synthetic productsbased on liquid mixtures of saturated hydrocarbons can also be used,such as, for example, the products marketed by the company TOTAL underthe designation GEMSEAL®, particularly such as the product GEMSEAL® 60which is an isoparaffinic mixture originating from a totallyhydrogenated petroleum fraction.

Within the context of the preparation of a hydrophilic adhesivecomposition according to the invention, a concentration of liquidplasticizer will preferably be used of the order of 25 to 90% by weightwith respect to the total weight of the composition, preferably 30 to75% by weight with respect to the total weight of the hydrophilicadhesive composition.

Finally, the hydrophilic adhesive composition according to the inventioncomprises water. It will be possible to use any type of water accordingto the fields of application envisaged such as, for example, springwater, tap water, demineralised, purified, deionised, or sterilisedwater.

It will of course be possible to incorporate any adjuvant with thiswater which is useful for preserving these properties of purity or ofsterility with time.

Similarly, according to the application sought after, it will bepossible to introduce very low amounts of water of the order of 1% byweight with respect to the total weight of the composition or largeamounts ranging up to 60% or more by weight with respect to the totalweight of the composition.

Within the context of the present invention, adhesive compositions arepreferred which comprise of the order of 1 to 50% by weight of water andmore particularly 10 to 45% by weight with respect to the total weightof the composition.

A currently preferred composition of the invention comprises

-   -   a. 2 to 20 parts by weight of a thermoplastic elastomer of        average molar mass greater than or equal to 100,000 daltons,    -   b. 30 to 75 parts by weight of liquid plasticizer,    -   c. 2 to 30 parts by weight of tackifying product,    -   d. 1 to 45 parts by weight of water, and    -   e. 0.05 to 5 parts by weight of an amphiphilic ABA type block        copolymer comprising two terminal thermoplastic poly(styrene)        blocks A and one central elastomeric block B in which the        central block B is a poly(ethylene-butylene) sequence comprising        grafted hydrophilic groups, it being possible for said        amphiphilic copolymer ABA to be represented schematically by the        following structure        in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average        molar mass equal to 2,000 i.e. n=45, and which has an average        molar mass measured by gel permeation chromatography of 50,000        daltons.

The following compositions will more particularly be preferred from thehydrophilic adhesive compositions included in this latter composition:

A composition which comprises

-   -   a. 2 to 20 parts by weight of a thermoplastic elastomer of        average molar mass greater than or equal to 100,000 daltons,    -   b. 30 to 75 parts by weight of liquid plasticizer,    -   c. 5 to 25 parts by weight of tackifying resin,    -   d. 10 to 40 parts by weight of water, and    -   e. 0.05 to 5 parts by weight of an amphiphilic ABA type block        copolymer comprising two terminal thermoplastic poly(styrene)        blocks A and one central elastomeric block B in which the        central block B is a poly(ethylene-butylene) sequence comprising        grafted hydrophilic groups, it being possible for said        amphiphilic copolymer ABA to be represented schematically by the        following structure:    -   in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average        molar mass equal to 2,000 i.e. n=45 and which has an average        molar mass measured by gel permeation chromatography of 50,000        daltons.

A composition which comprises

-   -   a. 2 to 20 parts by weight of a thermoplastic elastomer of        average molar mass greater than or equal to 100,000 daltons,    -   b. 30 to 75 parts by weight of liquid plasticizer,    -   c. 8 to 15 parts by weight of low molecular weight polybutene,    -   d. 10 to 40 parts by weight of water, and    -   e. 0.05 to 5 parts by weight of an amphiphilic ABA type block        copolymer comprising two terminal thermoplastic poly(styrene)        blocks A and one central elastomeric block B in which the        central block B is a poly(ethylene-butylene) sequence comprising        grafted hydrophilic groups, it being possible for said        amphiphilic copolymer ABA to be represented schematically by the        following structure:    -   in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average        molar mass equal to 2,000 i.e. n=45 and which has an average        molar mass measured by gel permeation chromatography of 50,000        daltons.

A composition which comprises

-   -   a. 2 to 20 parts by weight of a thermoplastic elastomer of        average molar mass greater than or equal to 100,000 daltons,    -   b. 30 to 75 parts by weight of liquid plasticizer,    -   c. 2 to 20 parts by weight of hydrosoluble polymer,    -   d. 10 to 40 parts by weight of water, and    -   e. 0.05 to 5 parts by weight of an amphiphilic ABA type block        copolymer comprising two terminal thermoplastic poly(styrene)        blocks A and one central elastomeric block B in which the        central block B is a poly(ethylene-butylene) sequence comprising        grafted hydrophilic groups, it being possible for said        amphiphilic copolymer ABA to be represented schematically by the        following structure:    -   in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) of average molar        mass equal to 2,000 i.e. n=45 and which has an average molar        mass measured by gel permeation chromatography of 50,000        daltons.

A composition which comprises

-   -   a. 2 to 20 parts by weight of a thermoplastic elastomer of        average molar mass greater than or equal to 100,000 daltons,    -   b. 30 to 75 parts by weight of liquid plasticizer,    -   c. 8 to 15 parts by weight of a group of tackifying products        which is constituted of a low molecular weight polybutene and of        a hydrosoluble polymer and more particularly 10 parts by weight        of low molecular weight polybutene and 2 to 5 parts de        vinylpyrrolidone polymer,    -   d. 10 to 40 parts by weight of water, and    -   e. 0.05 to 5 parts by weight of an amphiphilic ABA type block        copolymer comprising two terminal thermoplastic poly(styrene)        blocks A and one central elastomeric block B in which the        central block B is a poly(ethylene-butylene) sequence comprising        grafted hydrophilic groups, it being possible for said        amphiphilic copolymer ABA to be represented schematically by the        following structure:    -   in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average        molar mass equal to 2,000 i.e. n=45 and which has an average        molar mass measured by gel permeation chromatography of 50,000        daltons.

Many fields exist in which the thermoplastic adhesive compositionsaccording to the invention can be used as soon as the hydrophiliccharacter enables an improvement to be provided to the adhesive.

In general, they present very many advantages and prove to beparticularly useful every time that it is necessary to apply, formedical, dermatological, pharmaceutical or cosmetic purposes, a deviceon the skin, a wound or the mucous membranes, e.g. a dressing or abandage for treating or protecting the skin, a wound, burns, a blister,deep, chronic or grave superficial dermo-epidermic lesions, forpreparing a patch for the topical or systemic release of actives, or forthe cleansing or the care of the skin, such as, for example, a scalingor anti-wrinkle product, for rendering an electrode adhesive or forfixing hygiene products intended to enter into contact with the skin,such as, for example, in nappies, for the preparation of adhesives formammary prostheses, or in stoma for example for joints employed inostomies.

By virtue of their aptitude to contain water or a hydrophilic active ina medium having a high hydrophobic content and vice versa, variouscompounds can be incorporated during the formulation of the hydrophilicadhesive composition, within the context of these applications. Thesecompounds can be adjuvants or actives which are commonly used in thedermatological, cosmetic or pharmacological fields. Antioxidants,preservatives, perfumes, fillers, odour absorbers, colouring materials,UV filters, electrolytes for carrying current, pH regulators,bactericides, magnetisable particles, microcapsules or microspheres canthus be incorporated for example as adjuvants.

The amounts of these various adjuvants are those which are classicallyused in the field considered and for example 0.01 to 20% by weight withrespect to the total weight of the composition. One or more activesselected from the following list can be incorporated as active agent:vitamins and their derivatives, glycerine, collagen, salicylic acid,aromatic essential oils, caffeine, anti-free radical actives, hydratingactives, depigmenting actives (such as kojic acid), liporegulatingactives, anti-acne actives, anti-ageing actives, softening actives,decongesting actives, anti-wrinkle actives, refreshing actives,keratolitic agents and healing accelerating agents, vascular protectingagents, anti-bacterial agents such as sulfadiazine silver, anti-fungalagents, antiperspirant agents, deodorant agents, skin conditioningagents, anaesthetising compounds, immunomodulators, nourishing agents,plant extracts such as, for example, green tea, Arnica, hamamelis . . ., trace elements, local anaesthetics, anti-inflammatories, hormones,menthol, retinoids, DHEA, extracts of algae, of fungi, of yeast, ofbacteria, hydrolysed, partially hydrolysed or non-hydrolysed proteins.This list is of course non-limiting.

The active(s) can for example be present at a concentration in the rangeof 0.01 to 20%, preferably 0.1 to 5%, better 0.5 to 3% of the totalweight of the composition.

These adjuvants or these actives, according to their nature, can beintroduced into the hydrophobic and lipophilic phase or into the aqueousphase. Of course, the person skilled in the art will take care to selectthe eventual additional actives or adjuvants and/or their amount suchthat the advantageous properties of cohesion, and of elasticity of thehydrophilic thermoplastic adhesive according to the invention not be orsubstantially not be altered by the addition envisaged.

Within the context of the preparation of products for medical,dermatological or cosmetic purposes such as, for example, patches,dressings, electrodes . . . , the hydrophilic adhesive layer whichserves as a reservoir of actives or of adjuvants is in general combinedwith a support.

Given that the adhesive composition is, in this case the coating of thehydrophilic adhesive composition is carried out onto an adequate supportof desired grammage, according to the technique which is well-known tothe person skilled in the art, designated under the name “hot melt”.

The choice of the support is made as a function of the properties whichare required (waterproofness, elasticity, etc.) according to the type ofproduct and the application sought after.

It can be presented as a film of variable thickness of 5 to 150 μm or asa non-woven, or a foam having a thickness of 10 to 500 μm. Thesesupports based on synthetic or natural materials are those which aregenerally used by the person skilled in the art in the field of theapplications mentioned above.

Polyethylene foams, polyurethane foams, PVC foams, polypropylene,polyamide, or polyester non-wovens, or complexes made based on a filmand on a non-woven, etc. can thus be cited.

Practically, it will be possible for the surface of the hydrophilicadhesive composition which is not linked to the support to be coveredwith a protective layer or film which can be peeled off before use ofthe product. It will be possible for the assembly thus formed to beitself packaged in a waterproof protection made for example by means ofpolyethylene-aluminium complexes or in blisters.

The characteristics and applications of the invention will be betterunderstood upon reading the following description of Examples ofembodiments. The whole of these elements is of course in no waylimiting, but is given solely as an illustration.

For reasons of simplicity, an example of synthesis of a representativeamphiphilic copolymer will be given which will be used in all theadhesive compositions given as Examples which follow.

The method of synthesis of this copolymer is described in thePreparation I below.

A reactor equipped with a condenser, equipped with a drier, a sievelinked to the vacuum and to nitrogen if the reaction is carried outunder an inert atmosphere, and a Dean-Stark, for removing the waterformed by azeotropic distillation, are used in order to carry out thesynthesis of this latter copolymer.

Preparation I

150 ml of toluene are introduced under nitrogen in a reactor. 20 g ofKraton G 1901® (maleated SEBS copolymer), marketed by the company SHELL,are added. Heat is given under reflux (about 110° C.) under agitationuntil total dissolution of the maleated SEBS copolymer. A solution ofPEGME of molar mass 2,000, marketed by the company Aldrich under thedesignation poly(ethyleneglycol)methylether 2000, is prepared apart.32.32 g of PEGME 2000 are thus dissolved under agitation by heating atits melting temperature in 100 ml of toluene. About 20 drops ofsulphuric acid are added to the solution of maleated SEBS copolymerobtained beforehand, still under agitation and under reflux. Thesolution of PEGME 2000 in toluene prepared beforehand is then added,still under agitation and under reflux. Thus, in this case, there are 4hydroxyl functions for each anhydride function. The mixture obtained iskept agitated under reflux until the completion of the reaction ofesterification, i.e. here about 30 to 40 minutes. The solution is thenprecipitated in the hot, at about 90 to 100° C., in 1.5 l of a 50/50water-ethanol mixture. After filtration, the residual solvents areremoved from the precipitate obtained by evaporation in the oven undervacuum at 40-50° C. It is necessary to remove the excess PEGME 2000which has not reacted during the synthesis, in order to purify theamphiphilic polymer obtained. For this, the amphiphilic polymer isre-dissolved in the hot at about 90-100° C., with agitation, in 100 to150 ml of toluene, and the solution obtained is again precipitated in1.5 litres of a 50/50 water/ethanol mixture. After filtration, therecovered precipitate is dried under vacuum at 40-50° C. Thispurification step is repeated (re-dissolution-precipitation and dryingunder vacuum) until the PEGME 2000 is totally removed. An amphiphiliccopolymer is thus obtained in which R₁ and R₂ represent aCH₃—O—(CH₂—CH₂—O—)_(n) group in which n=45 which has an average molarmass of the order of 50,000 daltons, measured by gel permeationchromatography, with tetrahydrofuran as solvent, at a rate of 1 ml perminute, on a column marketed by the company WATERS under the designationSTYRAGEL HR4, and with a refractive index detector.

EXAMPLES OF COMPOSITIONS ACCORDING TO THE INVENTION

Several adhesive compositions according to the invention have then beenprepared:

1) Adhesive Compositions in which the Tackifier is a Resin

They are prepared according to the following preparative method:

The mixture of the various constituents is made in a closed reactor,heated to a temperature which ranges between 100 and 130° C., accordingto the nature of the thermoplastic elastomer, so as to melt the latterelastomer.

The agitation is made by virtue of a mixer equipped with adeflocculating helix at a speed of about 500 rpm.

Firstly, the amphiphilic copolymer, the water, the liquid plasticizer (amineral oil in the following Examples) and all the other compounds,actives or adjuvants, which are not susceptible to being degraded atthis temperature, except the tackifying product, which is here atackifying resin, and the thermoplastic elastomer, are introduced intothe reactor heated between about 100 and 130° C. The mixture thus formedis then agitated continuously until a homogeneous mixture is obtained.

Secondly, the tackifying resin is then introduced, keeping at the sametemperature, and agitation is continued until a homogeneous mixture isobtained.

The thermoplastic elastomer is then incorporated into this mixture andagitation is continued keeping between 100 to 130° C., until ahomogeneous mixture is obtained. If necessary, the thermoplasticelastomer can be mixed and melted with a small part of the liquidplasticizer before incorporation, in order to facilitate itshomogenisation with the preceding mixture.

If necessary, the temperature is allowed to cool to less than 100° C.and any compound which is susceptible to being degraded at a highertemperature, such as, for example, liposoluble or hydrosoluble adjuvantsand actives, such as a dry extract of Hamamelis in Example 2, is thenincorporated, and agitation is done until a homogeneous mixture isobtained.

The constituents used for the preparation of the hydrophilic adhesivecompositions described below in the Examples 1 to 4 are the following:PREPARATION I amphiphilic copolymer KRATON D 1161 ® SIS marketed by thecompany SHELL KRATON G 1651 ® SEBS marketed by the company SHELL ONDINA15 ® mineral oil marketed by the company SHELL ESCOREZ 5300 ® tackifyingresin marketed by the company EXXON CHEMICAL WATER METHYLPARABENhydrophobic preservative PROPYLPARABEN hydrophilic preservative EXTRACTof HAMAMELIS hydrophilic active marketed by the company SEPPIC

The amounts of the various constituents of these hydrophilic adhesivecompositions expressed in percentages by weight with respect to thetotal weight of the composition are grouped together in Table I. TABLE IEX. 1 EX. 2 EX. 3 EX. 4 PREPARATION I 2.7 4 2 2 KRATON G 1651 ® 2.7KRATON D 1161 ® 5 7 4 ONDINA 15 ® 32.1 46 43 35 ESCOREZ 5300 ® 15.7 6 127 WATER 46.8 38.6 36 52 METHYLPARABEN 0.2 PROPYLPARABEN 0.2 EXTRACT 0.4Of HAMAMELIS

2) Adhesive Composition in which the Tackifier is a HydrosolublePolymer.

Example 5

In a closed, double-envelope reactor heated at a temperature whichranges between 90 and 100° C., the following are incorporated,successively, under agitation by virtue of a mixer equipped with adeflocculating helix, at a speed of about 500 to 800 rpm: 1 g ofamphiphilic copolymer obtained according to the Preparation I, 29.4 g ofwater, 7.36 g of polyvinylpyrrolidone polymer marketed by the companyBASF under the designation Kollidon® 30, 56.8 g of plasticizer (liquidmixture of saturated hydrocarbons) marketed by the company TOTAL underthe designation GEMSEAL® 60, 0.2 g of hydrophobic preservative(Methylparaben) and 0.2 g of hydrophilic preservative (Propylparaben).

This agitation is maintained keeping at a temperature of between 90 and100° C., until a homogeneous mixture is obtained.

5 g of VECTOR® DPX-565, mixture of triblocks copolymer(styrene-isoprene-styrene) and of diblocks copolymer (styrene-isoprene),marketed by the company EXXON MOBIL Chemical, are then introduced,keeping at a temperature of between 90 and 100° C. and under agitation.Agitation is continued keeping at the same temperature until ahomogeneous mixture is obtained.

This mixture is the hydrophilic adhesive composition which is ready foruse.

3) Adhesive Composition in which the Tackifier is a Low Molecular WeightPolybutene.

Example 6

In a closed, double-envelope reactor equipped with a mixer equipped witha deflocculating helix, heated at a temperature which ranges between 90and 100° C., the following are incorporated successively: 55.6 g deGEMSEAL® 60 (liquid plasticizer), 10 g of low molecular weightpolybutene marketed by the company BP Chemical under the designationNAPVIS® 10.

1 g of amphiphilic copolymer obtained according to the Preparation I, 23g of water, 0.2 g of hydrophobic preservative (Methylparaben), 0.2 g ofhydrophilic preservative (Propylparaben) are then introduced keeping ata temperature of between 90 and 100° C., and agitating at a speed of 800rpm, until a homogeneous mixture is obtained.

10 g of VECTOR® DPX-565, are then incorporated, keeping at the sametemperature, and agitation is kept at 800 rpm until a homogeneousmixture, which constitutes the hydrophilic adhesive composition, isobtained.

4) Hydrophilic Adhesive Composition in which a Tackifier is Incorporatedin the Hydrophilic Phase and a Tackifier is Incorporated in theHydrophobic Phase

Example 7

55.6 g of GEMSEAL® 60 and 10 g of NAPVIS® 10 are introduced successivelyinto a closed, double-envelope reactor equipped with a mixer equippedwith a deflocculating helix, heated at a temperature of between 90 and100° C., under agitation at a speed of about 800 rpm, until ahomogeneous mixture is obtained. 1 g of amphiphilic copolymer obtainedaccording to the Preparation I, 18.44 g of water, 4.56 g of Kollidon®30, 0.2 g of Methylparaben and 0.2 g of Propylparaben are thenintroduced keeping at a temperature of between 90 and 100° C., andagitating at a speed of 800 rpm. Agitation is continued until ahomogeneous mixture is obtained.

10 g of VECTOR® DPX-565 are then introduced and agitation is kept at thesame speed, keeping at the same temperature, until a homogeneousmixture, which constitutes the hydrophilic adhesive composition, isobtained.

In the 3 preceding Examples, it will, as before, be possible tooptionally mix the VECTOR® DPX-565 (thermoplastic elastomer) with asmall amount of GEMSEAL® 60 (liquid plasticizer), taken from the totalamount incorporated at the start of the preparative examples, before itsincorporation in the mixture, in order to facilitate its homogenisationwith the latter.

The hydrophilic adhesive compositions are then ready to be used forexample incorporated in a product such as a patch.

In the case of Example 2, the adhesive composition has thus beendeposited which contains a hydrophilic active and preservatives on asupport, which is here a non-woven marketed by the company KURARAY, forthe preparation of a patch product which can be used as a product forthe care, the cleansing or the treatment of the skin, by virtue of itsastringent, decongesting, calming and antibacterial properties of theextract of Hamamelis.

The analysis of Table I illustrates the originality of the compositionsaccording to the present invention.

It is thus noted that it was possible to incorporate water in an amountranging up to 52% in Example 4, in an adhesive composition.

Similarly, it was possible to incorporate a mixture of hydrophilic andhydrophobic adjuvants, the parabens, and a hydrophilic active, theextract of Hamamelis, in the Example 2.

Finally, when the product based on Hamamelis of Example 2 is applied onthe skin, it is noted that it brings about a very pleasant sensation offreshness due to its relatively high water content (38.6%).

Similarly, Examples 5 to 7 illustrate the possibilities of preparing ahydrophilic adhesive composition (the percentage of water ranges fromabout 20 to 30%) by adjusting the addition of a tackifier in thehydrophilic phase (Example 5), in the hydrophobic phase (Example 6) orin both (Example 7).

The present invention thus appears to be particularly advantageous,insofar as it enables having for the first time in the state of the arthydrophilic adhesive compositions at one's disposal which enablepre-determined amounts of water or of hydrophilic compounds to beincorporated with compositions which possess good properties ofadhesion, of cohesion and of elasticity, and offers many possibilitiesfor regulating the adhesive properties of these compositions.

The compositions thus obtained can be used in a wide range ofapplications, particularly for the preparation of products for cosmetic,pharmaceutical, dermatological or medical usage, which are intended tobe placed in contact with the skin.

1. A hydrophilic adhesive composition, which comprises: a thermoplasticelastomer, which is selected from the group consisting ofpoly(styrene-olefin-styrene) block copolymers, poly(styrene-olefin)block copolymers and their mixtures, a tackifying product, a liquidplasticizer, water, and an amphiphilic ABA type block copolymercomprising two terminal thermoplastic poly(styrene) blocks A and onecentral elastomeric block B in which the central block B is apoly(ethylene-butylene) sequence comprising grafted hydrophilic groups,it being possible for said amphiphilic copolymer ABA to be representedschematically by the following structure:

in which R₁ and R₂, which are identical or different, represent ahydrophilic group of average molar mass less than 10,000, selected fromthe group consisting of:

in which n, a and b represent an integer.
 2. The hydrophilic adhesivecomposition according to claim 1, wherein the amphiphilic copolymer isan amphiphilic ABA type block copolymer comprising two terminalthermoplastic poly(styrene) blocks A and one central elastomeric block Bin which the central block B is a poly(ethylene-butylene) sequencecomprising grafted hydrophilic groups, it being possible for saidamphiphilic copolymer ABA to be represented schematically by thefollowing structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass preferably of between 1,000 and 8,000.
 3. The hydrophilic adhesivecomposition according to claim 2, wherein the amphiphilic copolymer hasan average molar mass measured by gel permeation chromatography of theorder of 50,000 daltons.
 4. The hydrophilic adhesive compositionaccording to claim 1 which comprises 0.05 to 20% by weight of saidamphiphilic copolymer with respect to the total weight of thecomposition.
 5. The hydrophilic adhesive composition according to claim1 which comprises 1 to 50% by weight of tackifying product(s) withrespect to the total weight of the hydrophilic adhesive composition. 6.The hydrophilic adhesive composition according to claim 5, wherein thetackifying product is compatible with the hydrophobic phase of thehydrophilic adhesive composition.
 7. The hydrophilic adhesivecomposition according to claim 6, wherein the tackifying product isselected from the group consisting of tackifying resins, low molecularweight polybutenes and their mixtures.
 8. The hydrophilic adhesivecomposition according to claim 7, wherein the tackifying product is atackifying resin which is present in a proportion of 5 to 25% by weightwith respect to the total weight of the hydrophilic adhesivecomposition.
 9. The hydrophilic adhesive composition according to claim7, wherein the tackifying product is a low molecular weight polybutenepresent in a proportion of 5 to 30% by weight with respect to the totalweight of the hydrophilic adhesive composition.
 10. The hydrophilicadhesive composition according to claim 5, wherein the tackifyingproduct is compatible with the aqueous phase of the hydrophilic adhesivecomposition and is selected from the group consisting ofnon-cross-linked, synthetic water-soluble polymers.
 11. The hydrophilicadhesive composition according to claim 10, which comprises 1 to 30% byweight of tackifying product with respect to the total weight of thecomposition.
 12. The hydrophilic adhesive composition according to claim5, which comprises 8 to 25% by weight with respect to the total weightof the composition of a group of tackifying products which isconstituted of a tackifying product which is compatible with the oilyphase and of a tackifying product which is compatible with the aqueousphase.
 13. The hydrophilic adhesive composition according to claim 1,wherein the liquid plasticizer is a plasticizing oil or a liquid mixtureof saturated hydrocarbons which is compatible with the central olefinicsequence of the thermoplastic elastomer.
 14. The hydrophilic adhesivecomposition according to claim 13, which comprises 20 to 90% by weightof liquid plasticizer with respect to the total weight of thecomposition.
 15. The hydrophilic adhesive composition according to claim1 wherein the thermoplastic elastomer is a mixture ofpoly(styrene-olefin-styrene) copolymer and of poly(styrene-olefin)copolymer.
 16. The hydrophilic adhesive composition according to claim 1wherein the olefinic sequence of said thermoplastic elastomer isselected from the group consisting of isoprene, butadiene,ethylene-butylene and ethylene-propylene.
 17. The hydrophilic adhesivecomposition according to claim 1 wherein the thermoplastic elastomer ispresent at a concentration of 2 to 20% by weight with respect to thetotal weight of the composition.
 18. The hydrophilic adhesivecomposition according to claim 1 which comprises 1 to 50% by weight ofwater with respect to the total weight of the composition.
 19. Ahydrophilic adhesive composition which comprises: a. 2 to 20 parts byweight of a thermoplastic elastomer of average molar mass greater thanor equal to 100,000 daltons, b. 30 to 75 parts by weight of liquidplasticizer, c. 2 to 30 parts by weight of tackifying product, d. 1 to45 parts by weight of water, and e. 0.05 to 5 parts by weight of anamphiphilic ABA type block copolymer comprising two terminalthermoplastic poly(styrene) blocks A and one central elastomeric block Bin which the central block B is a poly(ethylene-butylene) sequencecomprising grafted hydrophilic groups, it being possible for saidamphiphilic copolymer ABA to be represented schematically by thefollowing structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2,000, i.e. n=45, and which has an average molar massmeasured by gel permeation chromatography of 50,000 daltons.
 20. Thehydrophilic adhesive composition according to claim 19, which comprises:a. 2 to 20 parts by weight of a thermoplastic elastomer of average molarmass greater than or equal to 100,000 daltons, b. 30 to 75 parts byweight of liquid plasticizer, c. 5 to 25 parts by weight of tackifyingresin, d. 10 to 40 parts by weight of water, and e. 0.05 to 5 parts byweight of an amphiphilic ABA type block copolymer comprising twoterminal thermoplastic poly(styrene) blocks A and one centralelastomeric block B in which the central block B is apoly(ethylene-butylene) sequence comprising grafted hydrophilic groups,it being possible for said amphiphilic copolymer ABA to be representedschematically by the following structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2,000, i.e. n=45, and which has an average molar massmeasured by gel permeation chromatography of 50,000 daltons.
 21. Thehydrophilic adhesive composition according to claim 19, which comprises:a. 2 to 20 parts by weight of a thermoplastic elastomer of average molarmass greater than or equal to 100,000 daltons, b. 30 to 75 parts byweight of liquid plasticizer, c. 8 to 15 parts by weight of lowmolecular weight polybutene, d. 10 to 40 parts by weight of water, ande. 0.05 to 5 parts by weight of an amphiphilic ABA type block copolymercomprising two terminal thermoplastic poly(styrene) blocks A and onecentral elastomeric block B in which the central block B is apoly(ethylene-butylene) sequence comprising grafted hydrophilic groups,it being possible for said amphiphilic copolymer ABA to be representedschematically by the following structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2,000, i.e. n=45, and which has an average molar massmeasured by gel permeation chromatography of 50,000 daltons.
 22. Thehydrophilic adhesive composition according to claim 19, which comprises:a. 2 to 20 parts by weight of a thermoplastic elastomer of average molarmass greater than or equal to 100,000 daltons, b. 30 to 75 parts byweight of liquid plasticizer, c. 2 to 20 parts by weight of hydrosolublepolymer, d. 10 to 40 parts by weight of water, and e. 0.05 to 5 parts byweight of an amphiphilic ABA type block copolymer comprising twoterminal thermoplastic poly(styrene) blocks A and one centralelastomeric block B in which the central block B is apoly(ethylene-butylene) sequence comprising grafted hydrophilic groups,it being possible for said amphiphilic copolymer ABA to be representedschematically by the following structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2,000, i.e. n=45, and which has an average molar massmeasured by gel permeation chromatography of 50,000 daltons.
 23. Thehydrophilic adhesive composition according to claim 19, which comprises:a. 2 to 20 parts by weight of a thermoplastic elastomer of average molarmass greater than or equal to 100,000 daltons, b. 30 to 75 parts byweight of liquid plasticizer, c. 8 to 15 parts by weight of a group oftackifying products which is constituted of a low molecular weightpolybutene and of a hydrosoluble polymer, d. 10 to 40 parts by weight ofwater, and e. 0.05 to 5 parts by weight of an amphiphilic ABA type blockcopolymer comprising two terminal thermoplastic poly(styrene) blocks Aand one central elastomeric block B in which the central block B is apoly(ethylene-butylene) sequence comprising grafted hydrophilic groups,it being possible for said amphiphilic copolymer ABA to be representedschematically by the following structure:

in which R represents a CH₃—O—(CH₂—CH₂—O)_(n) group of average molarmass equal to 2,000, i.e. n=45, and which has an average molar massmeasured by gel permeation chromatography of 50,000 daltons.
 24. Aproduct selected from the group consisting of medical, dermatological,cosmetological and pharmaceutical products which comprises a hydrophilicadhesive composition according to claim
 1. 25. A product as claimed inclaim 24, which is a product to be applied on the skin, a wound or themucous membranes.
 26. A product as claimed in claim 24 which is selectedfrom the group consisting of a dressing for treating or protecting awound, a blister, burns, or superficial dermo-epidermic lesions, a patchfor delivering actives via the topical or systemic route, a product forthe care, the cleansing or the protection of the skin or the mucousmembranes, an electrode, and a product for stoma.
 27. The hydrophilicadhesive composition according to claim 10 wherein the tackifyingproduct is selected from the group consisting of polyvinylpyrrolidonepolymers and polyvinylpyrrolidone copolymers.
 28. The hydrophilicadhesive composition according to claim 17 wherein the thermoplasticelastomer has an average molar mass greater than that of the amphiphiliccopolymer.